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University of Massachusetts Amherst

Selected Works

2008

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Regulation Of Cancer Stem Cells By P53, D. Joseph Jerry, Luwei Tao, Haoheng Yan Aug 2008

Regulation Of Cancer Stem Cells By P53, D. Joseph Jerry, Luwei Tao, Haoheng Yan

D. Joseph Jerry

The hypothesis that cancer stem cells are responsible for the chemoresistant and metastatic phenotypes of many breast cancers has gained support using cell-sorting strategies to enrich the tumor-initiating population of cells. The mechanisms regulating the cancer stem cell pool, however, are less clear. Two recent publications suggest that loss of p53 permits expansion of presumptive cancer stem cells in mouse mammary tumors and in human breast cell lines. These results add restriction of cancer stem cells as a new tumor suppressor activity attributed to p53.


Observations Of The Gas Reservoir Around A Star Forming Galaxy In The Early Universe, Brenda L. Frye, David V. Bowen, Mairead Hurley, Todd M. Tripp, Xiaohui Fan, Bradley Holden, Puragra Guhathakurta, Dan Coe, Tom Broadhurst, Eiichi Egami, G. Meylan Aug 2008

Observations Of The Gas Reservoir Around A Star Forming Galaxy In The Early Universe, Brenda L. Frye, David V. Bowen, Mairead Hurley, Todd M. Tripp, Xiaohui Fan, Bradley Holden, Puragra Guhathakurta, Dan Coe, Tom Broadhurst, Eiichi Egami, G. Meylan

Todd M. Tripp

We present a high signal-to-noise spectrum of a bright galaxy at z = 4.9 in 14 h of integration on VLT FORS2. This galaxy is extremely bright, i_850 = 23.10 +/- 0.01, and is strongly-lensed by the foreground massive galaxy cluster Abell 1689 (z=0.18). Stellar continuum is seen longward of the Ly-alpha emission line at ~7100 \AA, while intergalactic H I produces strong absorption shortward of Ly-alpha. Two transmission spikes at ~6800 Angstroms (A) and ~7040 A are also visible, along with other structures at shorter wavelengths. Although fainter than a QSO, the absence of a strong central ultraviolet flux …


Stream Simulation: An Ecological Approach To Providing Passage For Aquatic Organisms At Road-Stream Crossings Aug 2008

Stream Simulation: An Ecological Approach To Providing Passage For Aquatic Organisms At Road-Stream Crossings

Scott D. Jackson

No abstract provided.


Book V, Otto Vogl: Publications, 1981-1984, Jane C. Vogl Aug 2008

Book V, Otto Vogl: Publications, 1981-1984, Jane C. Vogl

Otto Vogl

Books I-XII include citations to Otto Vogl's publications and patents. Printed versions of these twelve volumes are also available in the Integrated Sciences and Engineering Library of the University of Massachusetts in Amherst. MA, Lederle Graduate Research Center. The printed volumes include the full reprints of all cited publications.


Superhydrophobicity And Contact-Line Issues, Lc Gao, Ay Fadeev, Tj Mccarthy Aug 2008

Superhydrophobicity And Contact-Line Issues, Lc Gao, Ay Fadeev, Tj Mccarthy

Lixin Gao

The wettability of several superhydrophobic surfaces that were prepared recently by simple, mostly single-step methods is described and compared with the wettability of surfaces that are less hydrophobic. We explain why two length scales of topography can be important for controlling the hydrophobicity of some surfaces (the lotus effect). Contact-angle hysteresis (difference between the advancing, θA, and receding, θR, contact angles) is discussed and explained, particularly with regard to its contribution to water repellency. Perfect hydrophobicity (θA/θR = 180°/180°) and a method for distinguishing perfectly hydrophobic surfaces from those that are almost perfectly hydrophobic are described and discussed. The Wenzel …


"Dear Colleague" Letter On Student Assignment Aug 2008

"Dear Colleague" Letter On Student Assignment

Kathryn A. McDermott

This is the U.S. Department of Education's original guidance to school districts on how to respond to the PICS decision.


Uncertainty Analysis In Mcp-Based Wind Resource Assessment And Energy Production Estimation, Matthew Lackner, Anthony L. Rogers, James F. Manwell Aug 2008

Uncertainty Analysis In Mcp-Based Wind Resource Assessment And Energy Production Estimation, Matthew Lackner, Anthony L. Rogers, James F. Manwell

Matthew Lackner

This paper presents a mathematical framework to properly account for uncertainty in wind resource assessment and wind energy production estimation. A meteorological tower based wind measurement campaign is considered exclusively, in which measurecorrelate- predict is used to estimate the long-term wind resource. The evaluation of a wind resource and the subsequent estimation of the annual energy production (AEP) is a highly uncertain process. Uncertainty arises at all points in the process, from measuring the wind speed to the uncertainty in a power curve. A proper assessment of uncertainty is critical for judging the feasibility and risk of a potential wind …


Optimal Choice Of Voluntary Traceability As A Food Risk Management Tool, Dm Souza Monteiro,, Julie Caswell Aug 2008

Optimal Choice Of Voluntary Traceability As A Food Risk Management Tool, Dm Souza Monteiro,, Julie Caswell

Julie Caswell

Traceability systems are information tools implemented within and between firms in food chains to improve logistics and transparency or to reduce total food safety damage costs. Information about location and condition of products is critical when food safety incidents arise. This paper uses a principal-agent model to investigate the optimal choice of voluntary traceability in terms of precision of information on a given attribute at each link of a food chain. The results suggest that four scenarios may emerge for the supply chain depending on the costs of a system and whether or not the industry can internalize total food …


Dendron-Based Model Systems For Flavoenzyme Activity: Towards A New Class Of Synthetic Flavoenzyme, Ss Agasti, St Caldwell, G Cooke, Bj Jordan, A Kennedy, N Kryvokhyzha, G Rabani, S Rana, A Sanyal, Vm Rotello Jul 2008

Dendron-Based Model Systems For Flavoenzyme Activity: Towards A New Class Of Synthetic Flavoenzyme, Ss Agasti, St Caldwell, G Cooke, Bj Jordan, A Kennedy, N Kryvokhyzha, G Rabani, S Rana, A Sanyal, Vm Rotello

Vincent Rotello

Three generations of water-soluble flavin dendrons have been synthesized and the role dendrimer generation has on the physical and catalytic properties of these assemblies has been investigated.


Adaptive Polymer Particles, Kyriaki Kalaitzidou, Alfred Crosby Jul 2008

Adaptive Polymer Particles, Kyriaki Kalaitzidou, Alfred Crosby

Alfred Crosby

Adaptable polymer particles that can change geometry, flow characteristics, and adsorption properties upon the stimulation of an environmental change, such as temperature, are fabricated by utilizing the residual stress developed at the interface of a bilayer. We propose a phase diagram that can be used to predict the shape and size of the adaptive polymer particles as a function of the material modulus, thickness ratio, and the bilayer’s lateral dimensions. The materials used are gold/titanium and polydimethylsiloxane, but the method is applicable to a wide range of material combinations. Initial demonstrations of this responsive control and its impact on properties …


Graphite Electrode As A Sole Electron Donor For Reductive Dechlorination Of Tetrachlorethene By Geobacter Lovleyi, Sarah M. Strycharz, Trevor L. Woodard, Jessica P. Johnson, Kelly P. Nevin, Robert A. Stanford, Frank E. Lӧffler, Derek Lovley Jul 2008

Graphite Electrode As A Sole Electron Donor For Reductive Dechlorination Of Tetrachlorethene By Geobacter Lovleyi, Sarah M. Strycharz, Trevor L. Woodard, Jessica P. Johnson, Kelly P. Nevin, Robert A. Stanford, Frank E. Lӧffler, Derek Lovley

Kelly Nevin

The possibility that graphite electrodes can serve as the direct electron donor for microbially catalyzed reductive dechlorination was investigated with Geobacter lovleyi. In an initial evaluation of whether G. lovleyi could interact electronically with graphite electrodes, cells were provided with acetate as the electron donor and an electrode as the sole electron acceptor. Current was produced at levels that were ca. 10-fold lower than those previously reported for Geobacter sulfurreducens under similar conditions, and G. lovleyi anode biofilms were correspondingly thinner. When an electrode poised at −300 mV (versus a standard hydrogen electrode) was provided as the electron donor, G. …


Fracture-Induced Alignment Of Surface Wrinkles, Charles J. Rand, Renee Sweeney, Mary Morrissey, Lauren Hazel, Alfred Crosby Jul 2008

Fracture-Induced Alignment Of Surface Wrinkles, Charles J. Rand, Renee Sweeney, Mary Morrissey, Lauren Hazel, Alfred Crosby

Alfred Crosby

We introduce a simple process for creating materials that produce osmotically-driven surface wrinkles with long-range alignment, sans lithographically-defined topography and selective oxidation. Mechanically-induced surface defects create stress discontinuities that convert the global biaxial stress state to local uniaxial stresses, producing aligned wrinkles across the surface.


Constraints On The Variability Of Quark Masses From Nuclear Binding, Thibault Damour, John Donoghue Jul 2008

Constraints On The Variability Of Quark Masses From Nuclear Binding, Thibault Damour, John Donoghue

John Donoghue

Based on recent work on nuclear binding, we update and extend the anthropic constraints on the light quark masses, with results that are more tightly constrained than previously obtained. We find that heavy nuclei would fall apart (because the attractive nuclear central potential becomes too weak) if the sum of the light quark masses m_u+m_d would exceed their physical values by 64% (at 95% confidence level). We summarize the anthropic constraints that follow from requiring the existence both of heavy atoms and of hydrogen. With the additional assumption that the quark Yukawa couplings do not vary, these constraints provide a …


Self-Assembly And Cross-Linking Of Fept Nanoparticles At Planar And Colloidal Liquid-Liquid Interfaces, P Arumugam, D Patra, B Samanta, Ss Agasti, C Subramani, Vm Rotello Jul 2008

Self-Assembly And Cross-Linking Of Fept Nanoparticles At Planar And Colloidal Liquid-Liquid Interfaces, P Arumugam, D Patra, B Samanta, Ss Agasti, C Subramani, Vm Rotello

Vincent Rotello

Terpyridine thiol functionalized FePt and Au NPs were self-assembled and cross-linked at the liquid−liquid interfaces using Fe(II) metal ion. Complexation of terpyridine with Fe(II) metal ion leads to NP network and affords stable membranes and colloidal shells at the liquid−liquid interfaces.


Self-Trapping Of Optical Vortices In Waveguide Lattices With A Self-Defocusing Nonlinearity, Dh Song, Cb Lou, Lq Tang, Xs Wang, W Li, Xy Chen, Kjh Law, H Susanto, Pg Kevrekidis, Jj Xu, Zg Chen Jul 2008

Self-Trapping Of Optical Vortices In Waveguide Lattices With A Self-Defocusing Nonlinearity, Dh Song, Cb Lou, Lq Tang, Xs Wang, W Li, Xy Chen, Kjh Law, H Susanto, Pg Kevrekidis, Jj Xu, Zg Chen

Panos Kevrekidis

We demonstrate the self-trapping of single- and double-charged optical vortices in waveguide lattices induced with a self-defocusing nonlinearity. Under appropriate conditions, a donut-shaped single-charged vortex evolves into a stable discrete gap vortex soliton, but a double-charged vortex turns into a self-trapped quadrupole-like structure. Spectrum measurement and numerical analysis suggest that the gap vortex soliton does not bifurcate from the edge of the Bloch band, quite different from previously observed gap spatial solitons. Our numerical findings are in good agreement with experimental observations.


Integrating Cell Cycle Progression, Drug Penetration And Energy Metabolism To Identify Improved Cancer Therapeutic Strategies, Raja Venkatasubramanian, Michael A. Henson, Neil S. Forbes Jul 2008

Integrating Cell Cycle Progression, Drug Penetration And Energy Metabolism To Identify Improved Cancer Therapeutic Strategies, Raja Venkatasubramanian, Michael A. Henson, Neil S. Forbes

Michael A Henson

The effectiveness of chemotherapeutic drugs in tumors is reduced by multiple effects including drug diffusion and variable susceptibility of local cell populations. We hypothesized that quantifying the interactions between drugs and tumor microenvironments could be used to identify more effective anti-cancer strategies. To test this hypothesis we created a mathematical model that integrated intracellular metabolism, nutrient and drug diffusion, cell-cycle progression, cellular drug effects, and drug pharmacokinetics. To our knowledge, this is the first model that combines these elements and has coupled them to experimentally derived parameters. Drug cytotoxicity was assumed to be cell-cycle phase specific, and progression through the …


Book Vi, Otto Vogl: Publications, 1984-1986, Jane C. Vogl Jul 2008

Book Vi, Otto Vogl: Publications, 1984-1986, Jane C. Vogl

Otto Vogl

Books I-XII include citations to Otto Vogl's publications and patents. Printed versions of these twelve volumes are also available in the Integrated Sciences and Engineering Library of the University of Massachusetts in Amherst. MA, Lederle Graduate Research Center. The printed volumes include the full reprints of all cited publications.


Genome-Wide Gene Expression Patterns And Growth Requirements Suggest That Pelobacter Carbinolicus Reduces Fe(Iii) Indirectly Via Sulfide Production, Derek Lovley, Shelley A. Haveman, Raymond J. Didonato Jr, Laura Villanueva, Evgenya S. Shelobolina, Bradley L. Postier, Bo Xu, Anna Liu Jul 2008

Genome-Wide Gene Expression Patterns And Growth Requirements Suggest That Pelobacter Carbinolicus Reduces Fe(Iii) Indirectly Via Sulfide Production, Derek Lovley, Shelley A. Haveman, Raymond J. Didonato Jr, Laura Villanueva, Evgenya S. Shelobolina, Bradley L. Postier, Bo Xu, Anna Liu

Derek Lovley

Although Pelobacter species are closely related to Geobacter species, recent studies suggested that Pelobacter carbinolicus may reduce Fe(III) via a different mechanism because it lacks the outer-surface c-type cytochromes that are required for Fe(III) reduction by Geobacter sulfurreducens. Investigation into the mechanisms for Fe(III) reduction demonstrated that P. carbinolicus had growth yields on both soluble and insoluble Fe(III) consistent with those of other Fe(III)-reducing bacteria. Comparison of whole-genome transcript levels during growth on Fe(III) versus fermentative growth demonstrated that the greatest apparent change in gene expression was an increase in transcript levels for four contiguous genes. These genes encode two …


'Learning By Doing': Adaptive Planning As A Strategy To Address Uncertainty In Planning, Sadahisa Kato, Jack F. Ahern Jul 2008

'Learning By Doing': Adaptive Planning As A Strategy To Address Uncertainty In Planning, Sadahisa Kato, Jack F. Ahern

Jack F. Ahern

Adaptive management, an established method in natural resource and ecosystem management, has not been widely applied to landscape planning due to the lack of an operational method that addresses the role of uncertainty and standardized monitoring protocols and methods. A review of adaptive management literature and practices reveals several key concepts and principles for adaptive planning: (1) management actions are best understood and practiced as experiments; (2) several plans/experiments can be implemented simultaneously; (3) monitoring of management actions are key; and (4) adaptive management can be understood as ‘learning by doing’. The paper identifies various uncertainties in landscape planning as …


Manipulating Microparticles With Single Surface-Immobilized Nanoparticles, J Zhang, S Srivastava, R Duffadar, Jm Davis, Vm Rotello, Mm Santore Jun 2008

Manipulating Microparticles With Single Surface-Immobilized Nanoparticles, J Zhang, S Srivastava, R Duffadar, Jm Davis, Vm Rotello, Mm Santore

Vincent Rotello

This experimental study explores the capture and manipulation of micrometer-scale particles by single surface-immobilized nanoparticles. The nanoparticles, approximately 10 nm in diameter, are cationic and therefore attract the micrometer-scale silica particles in an analyte suspension. The supporting surface on which the nanoparticles reside is negative (also silica) and repulsive toward approaching microparticles. In the limit where there are as few as 9 nanoparticles per square micrometer of collector, it becomes possible to capture and hold micrometer-scale silica particles with single nanoparticles. The strong nanoparticle−microparticle attractions, their nanometer-scale protrusion forward of the supporting surface, and their controlled density on the supporting …


The Problem Of Maintaining Compliance Within Stable Coalitions: Experimental Evidence, David M. Mcevoy∗, James J. Murphy, John M. Spraggon, John K. Stranlund Jun 2008

The Problem Of Maintaining Compliance Within Stable Coalitions: Experimental Evidence, David M. Mcevoy∗, James J. Murphy, John M. Spraggon, John K. Stranlund

John M. Spraggon

This study examines the performance of stable cooperative coalitions that form to provide a public good when coalition members have the opportunity to not comply with their commitments. A stable coalition is one in which no member wishes to leave and no non-member wishes to join. To counteract the incentive to violate their commitments, coalition members fund a third-party enforcer. This leads to the theoretical conclusion that stable coalitions are larger (and provide more of a public good) when their members must finance enforcement relative to when compliance is ensured without the need for costly enforcement. However, our experiments reveal …


The Problem Of Maintaining Compliance Within Stable Coalitions: Experimental Evidence, David M. Mcevoy, James J. Murphy, John M. Spraggon, John K. Stranlund Jun 2008

The Problem Of Maintaining Compliance Within Stable Coalitions: Experimental Evidence, David M. Mcevoy, James J. Murphy, John M. Spraggon, John K. Stranlund

John K. Stranlund

This study examines the performance of stable cooperative coalitions that form to provide a public good when coalition members have the opportunity to not comply with their commitments. A stable coalition is one in which no member wishes to leave and no non-member wishes to join. To counteract the incentive to violate their commitments, coalition members fund a third-party enforcer. This leads to the theoretical conclusion that stable coalitions are larger (and provide more of a public good) when their members must finance enforcement relative to when compliance is ensured without the need for costly enforcement. However, our experiments reveal …


Disk-Shaped Bose-Einstein Condensates In The Presence Of An Harmonic Trap And An Optical Lattice, T Kapitula, Pg Kevrekidis, Dj Frantzeskakis Jun 2008

Disk-Shaped Bose-Einstein Condensates In The Presence Of An Harmonic Trap And An Optical Lattice, T Kapitula, Pg Kevrekidis, Dj Frantzeskakis

Panos Kevrekidis

We study the existence and stability of solutions of the two-dimensional nonlinear Schrödinger equation in the combined presence of a parabolic and a periodic potential. The motivating physical example consists of Bose–Einstein condensates confined in an harmonic (e.g., magnetic) trap and an optical lattice. By connecting the nonlinear problem with the underlying linear spectrum, we examine the bifurcation of nonlinear modes out of the linear ones for both focusing and defocusing nonlinearities. In particular, we find real-valued solutions (such as multipoles) and complex-valued ones (such as vortices). A primary motivation of the present work is to develop “rules of thumb” …


Book Vii, Otto Vogl: Publications, 1987-1989, Jane C. Vogl Jun 2008

Book Vii, Otto Vogl: Publications, 1987-1989, Jane C. Vogl

Otto Vogl

Books I-XII include citations to Otto Vogl's publications and patents. Printed versions of these twelve volumes are also available in the Integrated Sciences and Engineering Library of the University of Massachusetts in Amherst. MA, Lederle Graduate Research Center. The printed volumes include the full reprints of all cited publications.


Information Literacy And General Education At Umass Amherst, Emily Alling, Isabel Espinal, Beth Lang, Anne Moore Jun 2008

Information Literacy And General Education At Umass Amherst, Emily Alling, Isabel Espinal, Beth Lang, Anne Moore

Isabel R Espinal

No abstract provided.


Synthetic "Chaperones'': Nanoparticle-Mediated Refolding Of Thermally Denatured Proteins, M De, Vm Rotello May 2008

Synthetic "Chaperones'': Nanoparticle-Mediated Refolding Of Thermally Denatured Proteins, M De, Vm Rotello

Vincent Rotello

Thermally denatured chymotrypsin, lysozyme and papain are substantially refolded towards their native conformation by gold nanoparticle bearing dicarboxylate sidechains.


Estrogen And Progesterone Induce Persistent Increases In P53-Dependent Apoptosis And Suppress Mammary Tumors In Balb/C-Trp53+/- Mice, Karen Dunphy, Anneke C. Blackburn, Haoheng Yan, Lauren R. O'Connell, D Joseph Jerry May 2008

Estrogen And Progesterone Induce Persistent Increases In P53-Dependent Apoptosis And Suppress Mammary Tumors In Balb/C-Trp53+/- Mice, Karen Dunphy, Anneke C. Blackburn, Haoheng Yan, Lauren R. O'Connell, D Joseph Jerry

Karen Dunphy

Introduction Treatment with estrogen and progesterone (E+P) mimics the protective effect of parity on mammary tumors in rodents and depends upon the activity of p53. The following experiments tested whether exogenous E+P primes p53 to be more responsive to DNA damage and whether these pathways confer resistance to mammary tumors in a mouse model of Li-Fraumeni syndrome. Methods Mice that differ in p53 status (Trp53+/+, Trp53+/-, Trp53-/-) were treated with E+P for 14 days and then were tested for p53-dependent responses to ionizing radiation. Responses were also examined in parous and age-matched virgins. The effects of hormonal exposures on tumor …


Estrogen And Progesterone Induce Persistent Increases In P53-Dependent Apoptosis And Suppress Mammary Tumors In Balb/C-Trp53+/- Mice, D. Joseph Jerry, K.A. Dunphy, A.C. Blackburn, H. Yan, L.R. O'Connell May 2008

Estrogen And Progesterone Induce Persistent Increases In P53-Dependent Apoptosis And Suppress Mammary Tumors In Balb/C-Trp53+/- Mice, D. Joseph Jerry, K.A. Dunphy, A.C. Blackburn, H. Yan, L.R. O'Connell

D. Joseph Jerry

Introduction - Treatment with estrogen and progesterone (E+P) mimics the protective effect of parity on mammary tumors in rodents and depends upon the activity of p53. The following experiments tested whether exogenous E+P primes p53 to be more responsive to DNA damage and whether these pathways confer resistance to mammary tumors in a mouse model of Li-Fraumeni syndrome. Methods Mice that differ in p53 status (Trp53+/+, Trp53+/-, Trp53-/-) were treated with E+P for 14 days and then were tested for p53-dependent responses to ionizing radiation. Responses were also examined in parous and age-matched virgins. The effects of hormonal exposures on …


Tuneable Pseudorotaxane Formation Between A Biotin-Avidin Bioconjugate And Cbpqt(4+), St Caldwell, G Cooke, A Cooper, M Nutley, G Rabani, V Rotello, Bo Smith, P Woisel May 2008

Tuneable Pseudorotaxane Formation Between A Biotin-Avidin Bioconjugate And Cbpqt(4+), St Caldwell, G Cooke, A Cooper, M Nutley, G Rabani, V Rotello, Bo Smith, P Woisel

Vincent Rotello

A biotinylated 1,5-dialkoxynaphthalene derivative has been shown to have the ability to bind strongly to avidin and thus act as an artificial binding site for cyclobis(paraquat-p-phenylene) thereby facilitating the formation of a tuneable pseudorotaxane-based bioconjugate.


Book Viii, Otto Vogl: Publications, 1989-1992, Jane C. Vogl May 2008

Book Viii, Otto Vogl: Publications, 1989-1992, Jane C. Vogl

Otto Vogl

Books I-XII include citations to Otto Vogl's publications and patents. Printed versions of these twelve volumes are also available in the Integrated Sciences and Engineering Library of the University of Massachusetts in Amherst. MA, Lederle Graduate Research Center. The printed volumes include the full reprints of all cited publications.